Traffic markers



April 26, 1960 v. 1.. DUVAL D'ADRIAN 2,933,989

TRAFFIC MARKERS Filed Nov. 25, 1955 CELLULOSE ETHYL ETHE R I00 90 8O 7O6O 5O 4O 3O 20 IO 0 CASTOR WAX B ROSIN INVENTOR VINCENT L. DUVALD'ADRIAN ATTORNEY TRAFFIC MARKERS Vincent L. Duval dAdrian, Shrewshnry,Mo.

Application November 25, 1955, Serial No. 548,865

7 Ciaims. (Ci. 94-15) This invention relates to improvements in traflicmarkers. More particularly this invention relates to improve ments intraffic marking compositions and in methods of installing suchcompositions.

It is therefore an object of the present invention to provide animproved trafiic marking composition and an irnproved method ofinstalling such composition.

In guiding and directing trafiic, both vehicular and pedestrian, it ishelpful to have markings directly on the areas on which the traflicmoves. These areas are frequently surfaced with concrete or asphalt; andthe markings are usually applied directly to such surfaces. Thosemarkings are of two general types: one, a fluid that is painted on, orotherwise applied to, the trafiicbearing areas and then permited toharden; and two, solids in the form of tile that are secured to thetrafficbearing areas by asphalt coatings. One aspect of the presentinvention is to provide a traffic marking composition that can beapplied to traflic-bearing areas in either the fluid state or the solidstate. It is therefore an object of the present invention to provide atrafiic marking composition that can be applied to traflic-bearing areasin either the fluid state or the solid state.

The fact that the traffic marking composition of the said one aspect ofthe present invention can be applied to trafiic-bearing areas while itis in the fluid state is important since it is frequently important todesignate trafiic lanes by continuous strips or lines, and such stripsor lines are most easily formed by trafiic marking compositions in thefluid state. Paint is a traflic marking composition in the fluid state,and it is widely used. However, the trafiic marking composition of thesaid one aspect of the present invention will be more viscous thanpaint, and it can therefore form a thicker, and longer-lived, trafficmarking than paint can form. This is very desirable because it assuresthe benefits of traffic marking for longer periods of time.

Many different kinds of traflic tile have been proposed, and some ofthem have ben used. Those tiles are customarily made from a plasticmaterial; and they are usually secured to the traffic-bearing areas bycoatings of asphalt. Those tiles are usually serviceable on smooth flatareas as long as the asphalt coatings hold them in place. Unfortunately,however, the coatings of asphalt are frequently incapable of resistingthe dislodging forces applied to the tile by vehicles. This, of course,is objectionable. The said one aspect of the present invention obviatesthis objection by providing a traflic tile that inherently possesses theability to adhere to trafficbearing areas. Such a tile does not requirea coating of asphalt; and hence it is not subject to displacement due tofailure of that coating of asphalt. It is therefore an object of thepresent invention to provide a traflic tile that inherently possessesthe ability to adhere to trafficbearing areas.

The composition used in making the traflic tile of the said one aspectof the present invention can be rendered fluid and then applied totraflic-bearing areas while in 2,933,989 Patented Aprr 26, 1960 fig Wthe fluid state. That composition will thereafter change from the fluidstate to the solid state; and it will inher' ently adhere to thetraffic-bearing area when it becomes solid.

The traffic marking composition provided by the said one aspect of thepresent invention includes a normally non-tacky rosin material thatresponds to heat to become tacky and adhesive in nature. When thetrafiic marking composition of the said one aspect of the present inven=tion is heated, the normally non-tacky material becomes tacky andadhesive in nature and renders the said trafiic marking compositiontacky and adhesive. As a result, that composition will adhere to atraflic-bearing area to which it is applied. It is therefore an objectof the said one aspect of the present invention to provide a traflicmarking composition which includes a normally non-tacky rosin materialthat becomes tacky in nature when it is heated.

The traffic marking composition provided by the present invention isheat softenable; and hence it can be softened, by the application ofheat, to the point where it will conform to irregularities in thesurfaces of the traffic-bearing areas. The resultant intimate contactbetween the traflic marking composition and the trafiicbearing areas isof the greatest importance because it eliminates any need of thatcomposition bridging low spots in the surfaces of the trafiic-bearingareas. 'The traflic marking composition is thus freed from the stressesand strains which a bridging action would entail. It is therefore anobject of the present invention to provide a traflic marking compositionwhich is heat softenable and which can be softened sufiiciently, by theapplication of heat, to conform to variations in the surfaces of thetrafic-bearing areas.

The traflic marking composition provided by the said one aspect of thepresent invention is a solid at ambient temperatures; and while itsoftens during the heating step used in installing that composition, ithardens almost immediately thereafter. Consequently, this traflicmarking composition does not require the long hardening or drying periodthat paints require; and hence traflic interruptions are minimal duringinstallation of this traflic marking composition. In addition, the factthat this traific marking composition does not require a coating ofasphalt also reduces the time required to install it.

To be commercially successful, a traflic marking composition must bestrongly resistant to wear in summer and Winter, and it must beresistant to the blows imparted to it by the skid chains used onvehicles in the winter. The present invention provides a traffic markingcomposition that is tough while being yieldable. It is therefore anobject of the present invention to provide a traflic marking compositionthat is tough while being yieldable.

It is frequently desirable to make trafiic markings light reflective.Some painted traffic markings have been made light reflective bysprinkling glass beads onto them as they were drying; and those beadswere very helpful as long as they were held by the paint. All toofrequently, however, those beads were dislodged by the rapidlyaccelerating or rapidly decelerating tires of vehicles. Further, sincethe beads were wholly at the upper surfaces of the painted trafficmarkings, those beads were the very first portions of those markings tobe worn away. Consequently, even when a good part of a painted markingremains, the beads may be gone. This is objectionable. The presentinvention obviates that objection by distributing light reflective beadsthroughout all portions of a traflic marking composition. The uppersurface of such a composition can wear away without reducing the lightreflective capability of that composition, because the resulting uppersurface will be impregnated with addi- 2,983,989 V V r tional reflectivebeads. It is therefore an object of the present invention to provide atrafiic marking composition throughout which light reflective beads areuniformly distributed.

It is of the greatest importance that the light reflective beads betightly held in traffic marking compositions. If those beads becomeseparated from the traffic marking compositions, those compositions willlose some of their light reflectivity; and further, dirt and road soilcan lodge in the sockets previously occupied by the beads. The presentinvention provides a traffic marking composition that has lightreflective beads and that tightly holds those beads. V Trafiic markingcompositions that have lightrefiective beads distributed uniformlythroughout the'm' tendto lose their light reflectivity because of dirt,discoloration and road soil; the beads tending to grip and hold the dirtand road soil on the tires of vehicles. The present invention obviatesthe loss of light reflectivity by providing a traflic markingcomposition that tends to shed dirt, discoloration and road soil. Thattrafiic marking composition strongly resists the application of dirt,discoloration and road soil to it, and it also quickly sheds any dirt,discoloration and road soil that may actually be applied to it. It istherefore an object of the preesnt invention to provide a trafiicmarking composition that sheds dirt, discoloration and road soil.

The traffic marking composition provided by the present invention isenabled to shed dirt, discoloration and road soil because it has a waxyphase distributed uniformly throughout it. That waxy phase is, in partat least, separated from the other phase of the traffic markingcomposition provided by the present invention; and it provides a waxyfeel for that composition. It is therefore an object of the presentinvention to provide a traffic marking composition which has a waxyphase that gives it a waxy feel.

The traffic marking composition provided by the present invention can becolored by distributing pigment uniformly throughout it. The color ofthat traffic marking composition will be fully effective at all timesbecause the waxy phase of that composition will keep dirt, discolorationand road soil from obscuring or aberrating that color. Hence, thetrailic marking composition provided by the present invention has anunusually high degree of a color quality.

Other and further objects andv advantages of the pres ent inventionshould become apparent from an examination of the drawing andaccompanying description.

"In the drawing and accompanying description several preferredembodiments of the present invention are shown and described but it isto be understood that the drawing and accompanying description are forthe purpose of illustration only and do not limit the invention and thatthe invention will be defined by the appended claims. The drawing is atrilinear chart showing the proportions of one preferred ternarycomposition usable in making the traffic marking composition of thepresent invention.

The traffic marking composition of the present invention is aform-retaining substantially Water-insoluble, relatively inelasticformulation that is resistant to flow at ambient temperatures, that hasa low degree of inflammability, that is not brittle, that has a highdegree of retention .for glass beads, that has a waxy feel, and that isheat softenable. In addition, that traffic marking composition may beformulated so it becomes tacky and adhesive in nature when it is heated.That composition will preferably be used as a vehicle for pigment, lightEelilective beads, abrasion resistant filler and reinforcing The waxyfeel of the trafiic marking composition is dominantly due to thepresence of a waxy material. The form-retention, the relativeinelasticity, the resistance to 4 l flow, and the high retention forglass beads are domi' nantly due to the presence of a strength-givingmaterial. The waxy material can be a single substance or it can be amixture of two or more substances; and similarly, the strength-givingmaterial can be a single substance or it can be a mixture of two or moresubstances. If the trafiic marking composition is to be formulated so itis tacky and adhesive in nature when heated, the strengthgiving materialwill usually be a mixture of two or more substances; one of thosesubstances being'a toughening material, and the other of thosesubstances being a heat softenable binding material.

A number of different toughening materials can be 7 used in preparingthe trathc marking composition of the present invention. The followingmaterials are believed to be representative of the toughening materialsthat can be used: cellulose ethyl ethers, cellulose propyl ethers, ethylhydroxyethyl cellulose mixed ethers, polyvinyl butyrals, and vinylacetate polymers. Each of these materials is resistant to flow atambient temperatures, is not dark in color, is substantiallywater-insoluble, has a low degree of infiammability, is relativelyinelastic, has a high molecular weight, and can be rendered compatiblewith a waxy material. While the above-identified list of tougheningmaterials is representative, it is not exhaustive; and other highmolecular weight toughening materials having similar properties can beused. For example, higher alkyl celluloses such as cellulose butylethers and cellulose amyl ethers should be usable, but they are not yetcommercially available. From the point of view of cost and availability,the cellulose ethyl esters are the most attractive of these tougheningmaterials.

A number of difierent waxy materials can be used in preparing thetrafiic marking composition of the present invention. The followingmaterials are believed to be representative of the waxy materials thatcan be used: hydrogenated castor oil, which is referred to commerciallyas castor wax, glycol distearate, glycol dipalmitate. polyethylene,oxidized polyethylene, carnauba wax, bees wax, candelilla Wax, palmiticacid and stearic acid. Each of these materials is substantiallywater-insoluble, is not dark in color, has a low degree ofinflammability, is a solid at room temperature, and can be renderedcompatible with a strength-giving materiaL- The compatibility of thesewaxy materials with strength-giving materials must not be permanentwhere the resulting composition is to be exposed to traflic; instead,the waxy material must separate out in part as a waxy phase. Thisseparation of the waxy material is important since is enables thatmaterial to provide a waxy feel for the traiiic marking compositionwhich enables that composition to shed dirt, discoloration and roadsoil. While the above-identified list of waxy materials isrepresentative, it is not exhaustive.

It is desirable that the waxy phase remain in the solid state after thetrafiic marking composition has been applied to the traflic-bearingarea. This means that the waxy material must have a melting point thatis high enough to enable the waxy phase to remain solid even though itis exposed to the direct rays of the summer sun. Some of theabove-listed waxy materials have melting temperatures that are highenough to permit their use in traffic marking compositions intended forthe torrid zone, other of the above-listed waxy materials have meltingpoints that are not high enough to permit their use in trafiic markingcompositions intended for the torrid zone but are high enough for use intraffic marking compositions intended for the temperate zones, and stillother of the waxy materials have such low melting points that they arebest used in traffic marking compositions intended for the frigid zones.For example, castor wax having a melting temperature of about eight-six(86) degrees centigrade, carnauba wax having a melting tem perature ofabout eight-five degrees centigrade, glycol distearate having a meltingtemperature of about seventy-seven (77) degrees centigrade, ca'ndelillaWax having a melting temperature of about seventy-five (75) degreescentigrade, and polyethylene and oxidized polyethylene having asoftening temperature of about one hundred (100) degrees centigrade arewell adapted for use in trafiic marking compositions intended for thetorrid zone. Castor wax having a melting temperature of about seventy(70) degrees centigrade, glycol dipalmitate having a melting range ofabout seventy (70) degrees Centigrade, stearic acid having a meltingrange of about sixty-nine (69) degrees centigrade, and palmitic acid h ving a melting range of about sixty-four (64) degrees Centigrade areadapted for use in traffic marking compositions intended for thetemperate zone. Castor wax having a melting temperature of about sixty(60) degrees Centigrade, and bees Wax having a melting temperature ofabout sixty-one (61) degrees centigrade are best adapted for use intrafiic marking compositions intended for the frigid Zone. It ispossible to use most of the higher melting temperature waxy materials intraffic marking compositions intended for the temperate zones and thefrigid zones as well as in traffic marking compositions intended for thetorrid zone; and similarly it is possible to use most of theintermediate melting temperature waxy materials in traffic markingcompositions intended for the frigid zones as well as in trafiic markingcompositions intended for the temperate zones. However, the low meltingtemperature waxy materials should be used only in tratlic markingcompositions intended for cool climates.

A number of different heat softenable binding materials can be used inpreparing the trailic marking composition of the present invention. Thefollowing materials are believed to be representative of the heatsoftenable binding materials that can be used: rosin, including woodrosin and gum rosin; modified rosin, including heat modified rosins,polymerized rosins, ester gums, hydrogenated resins and hydrogenatedrosin esters, maleic modified rosin esters, and epoxy modified rosinesters; natural rosin gums such as dammar gum and copal; and phnolformaldehyde resins of the oil-soluble non-heat hardeni, type. Whilethe above-identified list of heat softena'ole binding materials isrepresentative, it is not exhaustive. Any one of these heat softenablebinding materials can be formulated with a toughening material and awaxy material; and if desired, mixtures of two or more of these heatsoftenable binding materials can be formulated with a tougheningmaterial and a waxy material. Further, if desired, some of thesematerials can be mixed with heat softenable plastic materials that havebeen plasticized to have properties similar to rosin; and then theresultant mixture can be formulated with a toughening material and awaxy material. For example, a phenolformaldehyde resin of theoil-soluble non-heat hardening type can be mixed with polystyrene thathas been plasticized with a chlorinated biphenyl; and thereafter theresulting mixture can be formulated with a waxy material and atoughening material.

Each of the heat softenable binding materials listed above issubstantially water-insoluble, is available in grades that are not darkin color, has a low degree of iniiarnmability, is resistant to fiow atambient emperatures, becomes tacky and adhesive in nature in thepresence of heat, and is compatible with organic toughening materials.tom the point of view of cost, availability and general application,wood resin is the most attractive of the heat softenable bindingmaterials.

in formulating the trafl lc marking composition provided by the presentinvention, the amount of Waxy material that is used must exceed theamount of waxy material that can be dissolved or dispersed in thatcomposition. Such an arrangement makes certain that a waxy phase willseparate out and provide the essential dirt-shedding characteristic forthe trafiic mark ng composition. The extent to which the waxy materialcan be A wide range of traflic marking compositions is contemplated bythe present invention; and those compositions fall into two groups. Onegroup possesses the property of inherently adhering to traffic-bearingareas while the second group does not possess that property. The varioustoughening materials referred to herein can be used in the tralficmarking compositions of both groups. Similarly, the various waxymaterials referred to herein can be used in the trafiic markingcompositions of both groups. The heat softenable binding material willnot, however, be used, if at all, to an appreciable degree in thetraffic marking compositions of the second It is not practical to listall of the usable traflic marking compositions contemplated by thepresent invention. Instead, only a small representative number oftraffic marking compositions is being described in detail.

Each of the trafiic marking compositions described herein willpreferably have light reflective beads, pigment and fillers added tothem. InExample I the COu. plete formulation, including light reflectivebeads, ment and fillers, is given; but in the rest of the examples, forthe sake of brevity, only the percentages of the toughening material,the waxy material and the heat softenable binding material are given.Those percentages are, in all instances, based on weight rather thanvolume.

Example I One trafilc marking composition of the one group that has beenfound to be extremely useful and serviceable consists of sixty (60)pounds of wood rosin, thirty-six (36) pounds of castor wax having amelting temperature of about eighty-six (86) degrees centigrade, sixteen(16) pounds of cellulose ethyl ether having an ethoxyl content ofapproximately forty nine percent (49%) and a viscosity number of onehundred and fifty (150) c.p.s., one hundred pounds of seventy to onehundred (70-100) mesh glass beads, fifty (59) pounds of Ashes tine,thirty (30) pounds of one hundred (100) mesh mica, and twenty (20)pounds of titanium dioxide. In formulating this traffic markingcomposition, the Wood resin is obtained in the form of chips or lumps,usually through the breaking up of the contents of a barrel of rosin;and the castor wax is obtained in the form or flakes. The rosin andcastor wax are heated to a temperature of about three hundred (300)degrees Fahrenheit; and that temperature is maintained for about onehalf /2) hour. The rosin and castor wax are stirred and mixed duringthat one half /2) hour with an agitator, as for example a commercialdough mixer; and at the end of the one half /2) hour period, the rosinand castor wax are liquefied. The beads are then added; and the additionof the beads causes the temperature of the liquefied rosin and castorwax to drop. The stirring and heating are continued until thetemperature again reaches three hundred (300) degrees Fahrenheit; andthis usually takes about fifteen (15) minutes. The beads are held insuspension by the stirring and agitating action of the agitator; andwhile the agitating and stirring action continues, the asbestine andmica are added. As these fillers are taken up by the liquid, the pigmentis added. At this time the heads, the fillers, and the pigment are insuspension in the liquefied rosin and caster wax; and the mixture is ata temperature of about three hundred (389) degrees Fahrenheit. Thetemperature is thereupon raised to three hundred and fifty (350) degreesFahrenheit; and the temperature is stabilized at that level. Thecellulose ethyl ether is obtained in granular form, and it is passedthrough a forty (40) mesh screen as it is introduced into the mixture.That screen holds back any lumps and large particles that would have toolarge a volume-to-surface ratio to readily combine with the liquefiedrosin and castor wax 'toform a compatible system. The mixture ismaintained at the temperature of about three hundred and fifty (350)degrees Fahrenheit for about two (2) hours; and then the mixture ispermitted to cool to ambienttemperature.

On cooling, the rosin, the castor wax and the cellulose ethyl ether donot remain permanently compatible; instead, a waxy phase separates out.That waxy phase appears to be, at least in part, in finely dividedcrystalline form.

Prior to the completion of the separation of the waxy phase, the trafficmarking composition is slightly tacky; but upon the completion of thatseparation, the tramc marking composition is non-tacky. After thecompletion of the separation of the waxy phase, the tratfic markingcomposition is stifier than it was before that separation was complete.At the conclusion of the separation of the waxy phase, the trafficmarking composition can be handled and packaged readily.

Where titanium dioxide is used as the pigment for the tratfic markingcomposition, that composition will be white. If the trafiic markingcomposition is to be colored, the percentage of titanium dioxide shouldbe reduced, and a colored pigment should be substituted for the titaniumdioxide that has been left out. For example, if the traffic markingcomposition is to be made yellow in color, sixteen (16) pounds of leadchromate can be substituted for sixteen (16) of the twenty (20) poundsof titanium dioxide.

The percentage of light reflective beads that are to be added, and thesize of those beads, are not critical. However, it has been found thatglass beads smaller than one hundred (100) mesh do not provide the highdegree of reflectivity desired, and glass beads larger than seventy (70)mesh tend to retain and hold dirt, discoloration and road soil.

Asbestine is used in this formulation as a reinforcing and strengtheningfiller. However, other comparable fillers could be used.

Mica is used in this formulation as a wear-resistant andabrasion-resistant filler. However, other comparable fillers could beused.

The steps that are outlined above in the formulation of Example I of thetraflic marking composition of the present invention can be carried outin different sequences, but the particular sequence outlined above isparticular- 1y useful in facilitating the formulation of that trafficmarking composition. Where, as in Example I, the traffic markingcomposition is to be used as a vehicle for pigment, light reflectivebeads and fillers, it is desirable to admix' the waxy material and theheat softenable binding material first. This is done in the presence ofheat, and the resultant mixture liquefies rather readily. The pigment,light reflective beads and fillers can be dispersed throughout theresulting liquid with ease. Usually the light reflective beads will beadded first, then the fillers will be added, and finally the pigmentwill be added. Once these ingredients have been added and thoroughlyintermixed, the toughening agent can be added. The resulting compositionis retained in the form of a rather viscous liquid until all of theingredients are thoroughly intermixed; and thereafter the composition iscooled. If the trafiic marking composition is to be used as trafiicmarking tile, the composition will be poured onto platens and pressed tothe desired thickness. The desired dimensions and configurations for theindividual tratfic tile can then be obtained by cutting the pressed-outtrafiic marking composition; that cutting preferably being done whilethe pressed out composition is still warm. If desired, the trafiicmarking composition of Example I can be extruded from an extrusionpress; and the desired configuration for the traflic tile can beprovided by the die of that press.

If the traffic marking composition is to be stored in fluid form, itwill have a suitable solvent mixed with it.

For example, when the traffic marking compositionhas cooled to aboutseventy-five degrees centigrade, one (1) gallon of isopropyl alcohol canbe added for each two and one half (2.5) pounds of composition.Thereafter, the resulting mixture is held at a temperature just belowthe boiling point of the alcohol while the mixture is stirred; andfinally a paste-like consistency is attained.

If the traific marking composition of the present invention is to beused without light reflective beads, fillers or pigments. the abovesequence of steps can be altered by deleting appropriate step or steps.Thus, if light reflective beads are not to be used, the fillers can beadded after the waxy material and heat softenable binding material havebeen liquefied.

Care must be taken, during the formulation of Example 1 of the trafiicmarking composition of the present invention, to keep the tougheningmaterial, the heat softenable binding material and the waxy materialfrom forming a permanently compatible system. Similarly, care must betaken, during the formulation of any trar'iic marking compositionemploying castor wax, to keep the waxy material and the strength-givingmaterial from becoming permanently compatible. This need for care arisesfrom the fact that castor wax can be degraded, by pro longed heating atcertain temperature levels, to the point where its melting point isdecreased and its compatibility with the strength-giving material isincreased.

If the waxy material and the strength-giving material were permitted tobecome permanently compatible, the resulting composition could notprovide the waxy feel that is needed to shed dirt, discoloration androad soil. Further, such a permanently compatible system would bepermanently tacky and adhesive and would collect, rather than shed,dirt, discoloration and road soil.

The need for care is particularly great because the temperatures used toliquefy the admixed strength-giving material and Waxy material are highenough to cause thermal degradation or" the castor wax. For example woodrosin, cellulose ethyl ether and castor Wax can be made into apermanently compatible system by holding them at a temperature of twohundred and fifty (250) degrees Fahrenheit for forty-eight (48) hours;and yet a temperature of three, hundred and fifty (350) degrees is adesirable temperature to use in forming the temporarily compatiblesystem of the traffic marking composition of the present invention. Bylimiting the time during which the traffic marking compositions,containing castor wax, are held at elevated temperatures, thosecompositions can be kept from becoming permanently compatible.

in Example I, the mixture is held at a temperature (300) degreesFahrenheit for less than an hour, and the mixture is then held at threehundred and fifty (350) degrees Fahrenheit for just over two hours. Sucha heating schedule will render the rosin, the cellulose ethyl ether andthe castor wax temporarily, rather than permanently, compatible.

If a batch of the trafiic marking composition has to be held overnight,it can be kept in a heated state without becoming permanently compatibleby holding its temperature at about two hundred and ten (210) degreesFahrenheit.

In the event a batch of traffic marking composition ever becomespermanently compatible, it can be made temporarily compatible bychanging its composition. For example, a permanently compatible, andthus unusable, batch of resin, cellulose ethyl ether and castor wax canbe rendered temporarily compatible, and thus useful, by adding a smallamount of polyethylene.

The determination of whether a composition of a strength-giving materialand a waxy material is temporarily or is permanently compatible iseasily made. The permanently compatible mixture is a substantially clearliquid when hot and remains substantially clear upon cooling andhardening; while a temporarily compatible mixture is a substantiallyclear liquid when hot and becomes cloudy upon cooling and hardening.

A good part of the waxy material should separate out of the temporarilycompatible system when that system cools, thereby providing a waxyphase. However, the toughening material and the heat softenable bindingmaterial, where the strength-giving material includes both, should notseparate out appreciably, if at all. Instead, those latter materials,and a part of the waxy material should remain in mutually dispersedcondition. Consequently, the toughening material and the bindingmaterial must have a high compatibility for each other when cool as wellas when hot; while the waxy material must have a high compatibility forthe binding material and the toughening material when hot but must havea lower degree of compatibility for those materials when cool.

if desired, the toughening material, the waxy material and the heatsoftenable binding material of Example I could be used directly as atraflic marking composition. Preferably, however, it will be used as avehicle. It could, for example be used as a vehicle for pigment and afiller such as sand. It could also be used as a vehicle for pigment,sand and asbestine. However, that traflic marking composition willpreferably be used as a vehicle for light reflective beads, pigment andfillers. The nature and quantity of light reflective beads, pigment andfillers is not critical. The critical factor in the traffic markingcomposition of the present invention is the temporarily compatiblesystem of strength-giving material and an excess of waxy material. Thatsystem must be solid and tough at ambient temperatures, must be capableof being softened by the application of heat, and must have a waxy feelto shed dirt, discoloration and road soil. in addition, that systemshould be able to hold beads, fillers and pigment against dislodgementby the tires of vehicles.

Example I] Another traffic marking composition of the one group consistsof fifty (50) parts of hydrogenated rosin ester, thirty (30) parts ofglycol distearate, and twenty (20) parts of cellulose ethyl ether. Thehydrogenated rosin ester and the glycol distearate are admixed andheated until they melt. Thereafter the temperature is raised to aboutthree hundred and fifty (350) degrees Fahrenheit and the cellulose ethylether is added. The resulting mixture becomes compatible in about two(2) hours, depending upon the rate at which it is agitated and stirredand depending upon the total weight of the batch. The hydrogenated rosinester used in this example is Staybelite resin 742.

The resulting tramc marking composition can, as indicated above, be useddirectly for traific marking or can be used as a vehicle for lightreflective beads, pigment and filler. Preferably it will be used as avehicle for beads, pigment and filler.

Example III Another trailic marking composition of the one groupconsists of fifty-four (54) parts of wood rosin, thirtytwo (32) parts ofcandelilla wax, and fourteen (14) parts of polyvinyl butyral resin. Thepolyvinyl butyral resin used herein is resin XYSG. The wood rosin andthe candelilla wax are admixed and heated until they melt. Thereafterthe temperature is raised to about three hundred and sixty-five (365)degrees Fahrenheit and the polyvinyl butyral resin is added. Theresulting mixture becomes compatible in about one and one half (1 /2)hours, depending upon the rate at which it is agitated and stirred anddepending upon the total weight of the batch.

This particular traflic marking composition has a high degree ofretentivity for light reflective beads. Further, it has a high degree ofinherent adherency for traflicbearing areas.

10 Example I V Still another trafiic marking composition of the onegroup consists of thirty-seven (37) parts of Wood rosin, twenty-seven(27) parts of oil-soluble phenol formaldehyde resin, thirty-two (32)parts of castor wax having a melting temperature of about eighty-six(86) degrees centigrade, and fourteen (14) parts of polyvinyl butyral.The oil-soluble phenol formaldehyde resin is resin Br. 10282. Thepolyvinyl butyral is resin XYSG.

The wood rosin and the castor wax are admixed and heated until theymelt. Thereafter the temperature is raised to about three hundred andfifty (350) degrees Fahrenheit, and the polyvinyl butyral is added. Theresulting mixture becomes compatible in about one and three quarters(1%) hours, depending upon the rate at which it is agitated and stirredand depending upon the total weight of the batch. At this time thephenol formaldehyde resin is added, and the stirring and heating iscontinued until the mixture is homogeneous; this usually happeningwithin one quarter A) of an hour.

This particular traffic mark ng composition has a high degree ofrententivity for light reflective beads. Further, it has a high degreeof inherent adherency for trafficbearing areas.

Example V An example of a traffic marking composition of the second typeconsists of sixty (60) parts of cellulose ethyl ether and forty (40)parts of castor wax having a melting temperature of about eighty-six(86) degrees centigrade. The cellulose ethyl other is of the lowviscosity type (10 cps.) and has a forty-eight to forty-nine andone-half percent Mil-49.5%) ethoxyl content. The caster wax is heateduntil it melts; and thereafter the temperature is raised to about threehundred and seventy (370) degrees Fahrenheit, and the cellulose ethylether is added. The resulting mixture becomes compatible in about oneand one quarter (1%.) hours, depending upon the rate at which it isagitated and stirred and depending upon the total weight of the batch.

This tralfic marking composition will not be inherently adherent totraffic-bearing areas; and hence a bonding material must be used toaffix the tralfic marking composition to the tratfic-bearing area.However, this trafiic marking composition will have an adequateretentivity for light reflective beads.

Example V1 Another example of a traflic marking composition of thesecond type consists of seventy-five (75) parts of polyvinyl acetate andtwenty-five (25) parts of polyethylene. The polyvinyl acetate is resinAYAT, and the polyethylene is a low molecular Weight grade.

The polyethylene is heated until it melts; and thereafter thetemperature is raised to about three hundred and sixty-five (365)degrees Fahrenheit. The polyvinyl acetate is added; and the resultingmixture becomes uniformly dispersed within about one and three quarters(1% hours, depending upon the rate at which it is stirred and dependingupon the total weight of the batch. The resultant dispersion is quiteviscous; and it is tough and horn-like on cooling.

This particular trafiic marking composition has a very high retentivityfor light reflective heads, but it does not have an inherent adherencyfor traflic-bearing areas. Accordingly, this trafiic marking compositionmust be aflixed to the traffic-bearing area by a bonding material.

The trafiic marking compositions of the one group can be applied totraffic-bearing areas in three different ways; the particular way beingdependent upon the form which the trafiic marking composition is to havewhen it is applied to the traffic-bearing areas. Specifically, if thetrafiic marking compositions of the one group are to be applied in theform of tile, those compositions can be aflixed to traffic-bearing areasby .reason of their inherent adherency or by a bonding material. If thetraflic marking compositions of the one group are to be applied in theform of a continuous strip or line, those compositions can be applied tothe traflic-bearing areas in fluid form and then heated to bond them tothose areas. The traflic marking compositions of the second group mustbe applied to the trafic-bearing areas by a bonding material.

One bonding material that has been found to be very useful is apermanently compatible mixture of castor wax, a toughening material, anda heat softenable binding material. In particular a composition of aboutfifty-five (55) parts of wood rosin, thirty (30) parts of castor wax,and fifteen (15) parts of cellulose ethyl ether can be heated overnightat three hundred and fifty (350) degrees Fahrenheit to render itpermanently compatible. The resulting composition is tacky and adherentto trafficbearing areas and to traflic marking tile of plastic material.This composition will preferably be rendered fluid by a solvent, as forexample isopropyl alcohol. One very useful way of rendering the bondingcomposition fluid is to add the isopropyl alcohol to that composition asit is cooling down from the three hundred and fifty (350) degreeFahrenheit temperature. In doing so it will material is below theboiling point of the alcohol; otherwise a good part of the alcohol couldbe lost by evaporation.

The resulting fluid will have the form of a creamy suspension, and itcan be stored and transported in fluid form. The bonding material can beapplied with a brush or other suitable instrument; and the alcohol canthen be evaporated. To remove the alcohol solvent of the bondingmaterial, the flame of a blow torch can be played over the bondingmaterial after it has been applied to the traflic-bearing area. Thebonding material is then in condition to receive and tightly holdtrafiic marking tile; and it will hold those tile whether or not thosetile are made from traffic marking compositions of the one group or thesecond group.

It will be desirable to heat the bottom surfaces of the traflic markingtile, and to heat the bonding material, before the trafflc marking tileis pressed into engagement ,with the bonding material. The heat willdrive off any moisture on the bottom surface of the traflic marking tileor on the top surface of the bonding material. Further, that heat willenhance the adherence between the trafiic marking tile and the bondingmaterial.

The bonding material is not necessary where the trafiic marking tilesare inherently adherent; because those tiles can adhere to cleanconcrete, asphalt and the like. However, since it is not always easy orconvenient to clean the surfaces of traffic-bearing areas, it willusually be desirable to apply a thin coating of the bonding mate- ,rialor of some dust-laying material. When used in this manner, the bondingmaterial functions primarily as a dust-laying coating. -Such adust-laying coating could be made from paint, lacquer, rubber cement,bituminous material or the like; the primary requisite of the dustlayingcoating being that it provides a non-oily, dust-free surface. Such acoating is particularly useful where the traffic-bearing area is ofconcrete, because concrete tends to form a fine dust at its surface; andthat dust could interfere with the adherence of the traffic markingtiles to the concrete.

The tralfic marking tiles of the present invention are heat softenable;and the flame of the blow torch will quickly soften the bottom surfaceof the tiles. Usually, a bottom surface of the traflic marking tile canbe softened sufficiently in less than a minute. 'Ihereupon, the trafiiemarking tile is pressed against the traffic-bearing area or thedust-laying coating thereon, as the case may be. The bottom surface ofthat tile hardens quickly and if that tile has been applied to asubstantially fiat .traflicbearing area, the tile is then ready to beartrafiric.

be advisable to wait until the temperature of the bonding In the eventthe traffic-bearing area is not substantially smooth, the traflicmarking tile should not be permitted to harden quickly. Instead, theflame of the blow torch should be applied to the upper surface of thattraffic marking tile immediately after that tile has been pressed intoengagement with the traffic-bearing area or with the dust-layingcoating. That flame can soften that traffic marking tile to the pointwhere that tile conforms fully to the surface of the traffic-bearingarea.

During the flame-heating of the bottom of the traffic marking tile, thatbottom softens and becomes sticky. The waxy material, of course,softens; but the component that both softens and becomes sticky is thedispersion of the binding material and the toughening material. Thatdispersion hardens upon cooling and intimately bonds the tratfic markingtile to the traflic-bearing area.

Where the traffic marking compositions of the one group are to beapplied as a line or strip, the compositions can be rendered fluid inthe manner described above. Those compositions can be applied to thetraflic-beariug areas by extruding them onto those surfaces or byapplying them to those areas and then spreading them to the desiredwidth and thickness. Heat, usually provided by a flame, is then appliedto the strip or line until the solvent is evaporated and the tralficmarking compositions are fused into masses of uniform texture which arefree of bubbles. After cooling to ambient temperature the marking stripor line is ready to bear traflic.

The thickness of the resulting strip or line will be greater than thethickness of a painted line; and hence the strip or line of traflicmarking composition will last a good deal longer than a painted strip orline. Further, the strip or line of a traffic marking composition canhave light reflective beads distributed uniformly throughout it; andhence it can still be light reflective after its upper surface has, intime, worn away.

The strips or lines of traffic marking composition provided by thepresent invention will adhere tightly to the trafiic-bearing area.Furthermore, because they are applied in the form of a fluid, they willbe able to follow any irregularities in the surfaces of thetrafliic-bearing areas.

When the traflic marking compositions of the present invention are flameheated they tend to discolor. However, that discoloration disappearsquite quickly, even when trafiic is permitted to move over thosecompositions immediately after they are applied to the traffic-bearingareas. The discoloration disappears more readily in warm weather, but inany event it usually disappears within a twenty-four (24) hour period.

Where the tops of the trafiic marking compositions are flame heated tocause those compositions to conform intimately to rough surface, thosetops will be tacky for a short period of time. If the flow of trafiic isto be resumed almost immediately, it is advisable to sprinkle mica dustor glass beads onto those flame-heated tops. The beads or the mica dustform a temporary coating on the tops of the traflic marking compositionsthat keeps those compositions from accumulating excessive amounts ofdirt, discoloration or road soil during the short, tacky period. 7

In the chart of the drawing, cellulose ethyl ether having a viscosity ofone hundred and fifty cps. and an ethoxyl content of from forty-eight toforty-nine and one half percent (4 849.5%) is represented by coordinateA; castor wax having a melting temperature of about eighty-six (86)degrees centigrade is represented by coordinate B; and wood rosin isrepresented by coordinate C. 'These coordinates are demarked accordingto the percentages, by weight, which the cellulose ethyl ether, thecastor wax and the wood rosin bear to the overall composition of thethree. The quadrilateral polygon defined by the vertices W. X, Y and Zon the chart of the drawing includes a number of points representing.raflic marking compositions formed from various percentages ace-2,989

of cellulose ethyl ether, wood resin and castor wax. These traflicmarking compositions are particularly desirable because they arerelatively inexpensive, they are composed of readily availablematerials, and they are inherently adherent to traific-bearing areas.Vertex W is located at A10, B70 and C20; vertex X is located at A5, B15and C80; vertex Y is located at A10, B10 and C80; and vertex Z islocated at A58, B22 and C20. The trafiic marking compositionsrepresented by points within the polygon W, X, Y and Z possess theproperties and characteristics of trafic marking compositions of the onegroup; those trafiic marking compositions being resistant to impact andto wear, being inherently adherent, and having a waxy feel. Trafficmarking compositions, on the polygon W, X, Y and Z, having less thanfive percent by weight of cellulose ethyl ether tend to be unable towithstand satisfactorily the heavy impact of tires of vehicles and ofthe skid chains of vehicles during cold weather; and trafiic markingcompositions having more than sixty percent (60%) by weight of celluloseethyl ether tend to have less than the required compatibility of thecellulose ethyl ether and the wood rosin. Traffic marking compositions,on the polygon W, X, Y and Z, having less than twenty percent (20%) byweight of wood rosin tend to fail to have enough inherent adherency toadhere satisfactorily to the traffic-bearing surfaces; and traificmarking compositions having more than eighty percent (80%) by weight ofwood, rosin tend to be too brittle and to be insufiiciently resistant towear and abrasion. Trafiic marking compositions, on the polygon W, X, Yand Z, having less than ten percent castor wax by Weight do notsatisfactorily shed dirt and discoloration in all kinds of weather; andtrafiic marking compositions having more than seventy percent (70%) byweight tend to be insufficiently adherent to the trafficbearing areas ortend to be insuflicienfly tough and wearresistant.

Trafiic marking compositions of the second group are represented bypoints within the quadrilateral polygon defined by the vertices U, V, Wand X on the chart of the drawing. Other traffic marking compositions ofthe second group are represented by points on the line UV on the chartof the drawing. The vertex U is located at A75, B25 and C0, and thevertex V is located at A20, B80 and C0. The trafiic marking compositionsrepresented by points within the polygon U, V, W, and X, and by pointson the line UV, will have a waxy feel and will have impact resistanceand wear resistance and will also have a high retentivity for lightreflective heads, but they will not have any inherent adherency thatwill enable them to be applied to concrete without a bonding mate rial.However the bonding material described above will hold those trafficmarking compositions to concrete in a permanent and intimate manner.

Cellulose ethyl ether having a viscosity of one hundred and fifty (150)cps. and an ethoxyl content of fortyeight to forty-nine and one halfpercent (48-49.5%) is the preferred toughening material, but it ispossible to substitute for it any of the commercially availablecellulose ethyl ethers having viscosities above seven (7) cps. andethoxyl contents above forty-four and one half percent (44.5%). Further,it is possible to substitute any of the various toughening materialslisted above.

Wood rosin is the preferred binding material but it is possible tosubstitute gum rosin or any of the various heat softenable bindingagents listed above. Gum rosin, like wood rosin, is an inexpensive andreadily obtainable heat softenable binding material; but thesubstitution of gum rosin for Wood rosin makes the resulting trafficmarking composition harder when it is in the solid state. Further,traflic marking compositions using gum rosin instead of 'wood rosinrequire much more closely controlled temperatures during the mixingoperations. Unless the temperatures are controlled more closely thanwhen wood rosin is used, the traflic markers embodying gum rosin tend tohave insufiiicent adhesion to the tratlic-bearing areas. Moreover,traflic marking compositions with gum rosin usually require highertemperatures than do the compositions with wood rosin; and those highertemperatures tend to darken the gum rosin. Consequently more pigment isrequired with trafi'ic markers made with gum rosin.

Whereas .he drawing and accompanying description have described severalpreferred embodiments of the present invention, it should be apparent tothose skilled in the art that various changes may be made in the form ofthe invention without affecting the scope thereof.

What I claim is:

1. A form-retaining, heat softenable, traffic marking compositionsubstantially non-tacky at ambient temperature containing as theessential ingredients thereof a compatible phase and a separated waxyphase, said compatible phase consisting essentially of a substantiallywater-insoluble, toughening material of the group consisting ofcellulose alkyl ethers and alkyl hydroxyalkyl cellulose mixed ethers; aheat-softenable binding material of the group consisting of wood rosin,gum rosin, heat modified rosin, polymerized rosin, ester gum,hydrogenated rosin, hydrogenated rosin esters, maleic modified rosinesters and epoxy modified rosin esters; and castor wax, said castor waxconstituting part of said compatible phase and constituting saidseparated waxy phase, said ingredients being distributed uniformlythroughout said traffic marking composition, said compatible phaseconsisting essentially of about 558% of said toughening material, about20-80% of said binding material, and part of said castor wax, the totalamount of castor wax in said compatible phase and in said separated waxyphase being about 30-70% of the total weight of said compatible phaseplus said separated waxy phase.

2. A composition according to claim 1 including light reflective beadsuniformly distributed through it.

3. A composition according to claim 1 including a pigment.

4. A composition according to claim 2 including a pigment.

5. A composition according to claim 1 containing 55% by weight of woodrosin, 30% by weight of castor Wax and 15% of cellulose ethyl ether.

6. A composition according to claim 1 containing 60% by weight ofcellulose ethyl ether and 40% by weight of castor wax.

7. A process for marking a trafiic bearing area comprising heating acomposition defined in claim 1, applying said heated composition to atraffic bearing area, and permitting said traffic marking composition tocool whereby said composition becomes bonded to said trafiic hearingarea.

References Cited in the file of this patent UNITED STATES PATENTS1,729,834 Jackson Oct. 1, 1929 1,925,921 Godfrey Sept. 5, 1933 2,186,454Gloor Jan. 9, 1940 2,268,538 Rodli et al. Dec. 30, 1941 2,297,709 Kauppiet al. Oct. 6, 1942 2,311,609 Kauppi et al. Feb. 16, 1943 2,354,049Palmquist July 18, 1944 2,379,702 Gebhard July 3, 1945 2,393,525 FarrellJan. 22, 1946 2,413,011 Traylor et al. Dec. 24, 1946 2,574,971 HeltzerNov. 13, 1951 2,694,027 Calkins Nov. 9, 1954

